Thanks for your question. From what you are describing you may have a vitreous floater
. These floaters
are very common and if large enough they can obscure your vision. They tend to be more common in short-sighted people as their eyes are larger. By themselves they are nothing to worry about and your brain will adjust and start ignoring them with time.
However, if you are getting any new floaters, flashing lights or a curtain coming across your vision I would recommend an urgent dilated eye examination with your doctor. This is to rule out any retinal tears